In an exclusive interview to be aired on the "Dr. Phil" show Thursday, McGraw spoke with Castellano, 37, in Texas days after police say he snapped Warner's neck in the apartment the two shared while their 3-year-old son, Cayden, was in the next room.

"Dr. Phil" show spokeswoman Stacey Luchs released a statement Monday confirming the taping of the interview with Castellano in Texas last week.

"Mr. Castellano sat down for an interview with Dr. Phil in Texas just before his confession to law enforcement, late last week," she said in a statement. "Dr. Phil also conducted an interview with Ms. Warner's family for this show, which is currently scheduled to air on Thursday."

Luchs did not say whether Castellano confessed to the crime in the interview with McGraw. However, a later news release by the "Dr. Phil" show noted, "Castellano at times referred to her in the past-tense and even showed Dr. Phil her car, which is the very place he now claims to have kept her body for two days."

Det. Fil Waters of the Houston Police Department said Castellano shared the same information when taping the interview for the show that he had been sharing with investigators.

"I thought he was kidding, but it was the real deal," Waters said. "He talks to Dr. Phil, provides Dr. Phil, as I understand it, with the same information he's been providing everyone else."

Castellano, 37, was charged in court overnight with killing Warner and only spoke once, requesting a court appointed attorney, Houston affiliate KTRK-TV reported. He is being held on $150,000 bond.

It's unclear whether he has been assigned an attorney.

A missing persons report was filed by the family of Warner after they hadn't heard from her for several days. The 31-year-old's family told police that Warner disappeared after she and Castellano, with whom she was living but was no longer romantically involved, got into an argument Sept. 22. He then left Houston with their son to drive eight hours to see relatives in Odessa, Texas, according to Houston police.

Castellano remained in contact with investigators in Houston, and agreed to fly back from Odessa to meet with them Sunday. It was then that he admitted to his role in Warner's death, police said.

Castellano told police he choked Warner and heard her neck snap, and then stuffed her body in a closet with a plastic bag around her head.

Det. Waters said Cayden had walked around the corner and saw Warner's feet hanging off of a bed. Castellano said that he told the boy that "mommy's asleep."

"We had an argument," Waters said Castellano told them. "Couldn't take it anymore. I grabbed her around the throat, pushed her on to the bed, and I hear her neck snap."

Castellano told the Houston police that he then drove back to the Midland-Odessa area where he attempted to bury her body in an oilfield.

After he told investigators where Warner's body could be found in Midland, FBI agents working with the Odessa police recovered her body and Castellano was arrested.